In the continuous development of the modern highway and bridge engineering industry,the reasonable selection of mega highway bridges and their design is crucial.Based on this,this paper takes the actual bridge project...In the continuous development of the modern highway and bridge engineering industry,the reasonable selection of mega highway bridges and their design is crucial.Based on this,this paper takes the actual bridge project as an example,and analyses the overall selection design of such highway bridges,including the basic overview of the project,the basic selection principle of mega highway bridge project structure and its design strategy,etc.,to provide scientific reference for its selection design.展开更多
Traffic management in underground mines,especially on production ramps,is a difficult problem to optimize and control.Most operations use one of a few common policies;e.g.,the so-called ‘‘lock-out" and‘‘loade...Traffic management in underground mines,especially on production ramps,is a difficult problem to optimize and control.Most operations use one of a few common policies;e.g.,the so-called ‘‘lock-out" and‘‘loaded-vehicle-priority" policies.The work presented in this paper uses discrete-event simulation to study the efficiency of multiple policies.Based on simulation results,an improvement to the common lock-out policy is proposed.This new policy utilizes the rules of the lock-out policy but integrates an option that allows a group of vehicles to be given temporary priority in a certain direction of travel.Quantitative results are provided and,based on these,a systematic technique for ramp design that aims to optimize the efficiency of underground mine ramp traffic flow is described.展开更多
This paper mainly introduces the calculation and selection process of the feed mechanism of the truss manipulator. According to the handling load, beat and handling accuracy required by the production line, the three ...This paper mainly introduces the calculation and selection process of the feed mechanism of the truss manipulator. According to the handling load, beat and handling accuracy required by the production line, the three shaft transmission mechanism of the truss is calculated and selected.展开更多
It has been found that the rock breaking tools combination of positive displacement motors(PDM)with different output parameters(positive rotational speed and positive torque)and polycrystalline diamond compact(PDC)bit...It has been found that the rock breaking tools combination of positive displacement motors(PDM)with different output parameters(positive rotational speed and positive torque)and polycrystalline diamond compact(PDC)bits with different design features exhibits significant differences in rock breaking effi-ciency and stability.This indicates that studying the compatibility between PDC bit and PDM before conducting drilling process is necessary.TheΦ215.9 mm wellbore condition in Longmaxi formation was taken as an example,the positive rotational speed and positive torque exerted byΦ197mm PDM with different number of lobes and pitch length were calculated,PDC bit with different cutting strategies were designed.Then finite element method(FEM)models considering PDM output parameters were established to study rock breaking process.Required weight on bit(WOB),required mechanical specific energy(MSE),reaction torque on bit(TOB),and vibration characteristics at near-bit position under the designed rate of penetration(ROP)were obtained.Research results showed that:(1)The energy required for PDC bit with certain design features breaking shale is not a constant value,but a value changes with rotational speed and positive torque exerted by different PDM.(2)The ability controlling vibration of PDM tends to stabilize when the number of lobes N and pitch length h exceeds 5 and 140 mm respectively in general conditions,Thus combination design parameters when N=5,h=140 mm were suggested to balance rock breaking efficiency and service life of drill strings.(3)Compared with other cutting strategies,when rock breaking pattern consist of“face to face”interaction and“point to point”interaction,both rock breaking efficiency and stability were higher.While when matched with this cutting strategy,N=8 and h=140/200 mm were recommended for PDM design instead of N=5 and h=140 mm obtained in most cases,which cloud minimize the loss of rock breaking efficiency and improve the axial/circumferential stability by 14.24%–17.23%and 24.93%–35.73%respectively.An integrated selection and design method of PDC bit and PDM was established and implemented,which revealed the rock breaking efficiency and stability patterns of different rock breaking tools combinations,providing theoretical support and suggestions for the integrated selection and design of PDC bits and PDM in Longmaxi formation.展开更多
Spray drying is an important continuous industrial process for drying pumpable liquid formulations irrespective of their heat sensitivity, rheology, solids content and processing rate. Furthermore spray drying has the...Spray drying is an important continuous industrial process for drying pumpable liquid formulations irrespective of their heat sensitivity, rheology, solids content and processing rate. Furthermore spray drying has the capability through drying chamber design, plant layout and mode of operation to produce dried products of specific particulate size and morphology. These are important aspects when spray drying technology is applied to the needs of customized powder manufacture. There are many examples in industry where spray dried powders have to meet stringent specifications set by such factors as end-product powder quality standards dictated by global competition,dry raw material characteristics required for optimum downstream processing, and dry materials handling to comply with environmental, health and safety issues. Spray drying is no longer regarded just as a convective industrial drying concept, but also as an integral part of modern manufacturing practices applying powder technology. This paper reviews the aspects of spray dryer design and operation for consideration when customized powder manufacture is involved.展开更多
Selection of air conditioning（AC） cold/heat sources generally concerns about certain aspects and cannot reveal the whole profile of the problems. Grey relation analysis （GRA） is a data processing method to categor...Selection of air conditioning（AC） cold/heat sources generally concerns about certain aspects and cannot reveal the whole profile of the problems. Grey relation analysis （GRA） is a data processing method to categorize the correlation extent of compared sequences and a certain reference sequence in a system with uncertain information. It is applied to evaluating and selecting AC cold/heat sources from four main aspects, which are technology, economy, reliability, and operation and management. Case study shows that the result for selecting AC cold/heat sources with the GRA method can be more reasonable and convincible. Thus it offers a new approach for designers in heating, ventilating and air conditioning field to compare and evaluate different AC cold/heat sou rces.展开更多
China's road network consists of numerous older expressways experiencing high traffic volumes and severe congestion,necessitating urgent reconstruction and expansion efforts.This study discusses the reconstruction...China's road network consists of numerous older expressways experiencing high traffic volumes and severe congestion,necessitating urgent reconstruction and expansion efforts.This study discusses the reconstruction and expansion project of the Yinkun Expressway's Chongqing High-tech Zone to Rongchang District section,with a detailed exploration of the entire design process.Through a comprehensive analysis,the strengths and weaknesses of different plans are examined,so as to determine the optimal plan.The design chosen saves costs while effectively addressing traffic demands.Additionally,the study summarizes the valuable design insights gained from this interchange transformation,aiming to provide valuable reference for similar interchange projects in the future.展开更多
文摘In the continuous development of the modern highway and bridge engineering industry,the reasonable selection of mega highway bridges and their design is crucial.Based on this,this paper takes the actual bridge project as an example,and analyses the overall selection design of such highway bridges,including the basic overview of the project,the basic selection principle of mega highway bridge project structure and its design strategy,etc.,to provide scientific reference for its selection design.
基金funded by the Natural Science and Engineering Research Council of Canada (NSERC) under project CRDPJ 44SBO4-12funding provided by Barrick Gold Corporation and Peck Tech Consulting Ltd
文摘Traffic management in underground mines,especially on production ramps,is a difficult problem to optimize and control.Most operations use one of a few common policies;e.g.,the so-called ‘‘lock-out" and‘‘loaded-vehicle-priority" policies.The work presented in this paper uses discrete-event simulation to study the efficiency of multiple policies.Based on simulation results,an improvement to the common lock-out policy is proposed.This new policy utilizes the rules of the lock-out policy but integrates an option that allows a group of vehicles to be given temporary priority in a certain direction of travel.Quantitative results are provided and,based on these,a systematic technique for ramp design that aims to optimize the efficiency of underground mine ramp traffic flow is described.
文摘This paper mainly introduces the calculation and selection process of the feed mechanism of the truss manipulator. According to the handling load, beat and handling accuracy required by the production line, the three shaft transmission mechanism of the truss is calculated and selected.
基金CNPC(China National Petroleum Corporation)-SWPU(South-west Petroleum University)Innovation Consortium Project:Optimization research on drilling method and technology for complex formations in deep wells,Project ID:2020CX040103,2020/01-2025/12Essential Research and Development Plan by Department of Science and Technology in Sichuan Province(International Science and Technology Innovation Cooperation/Hong Kong Macao Taiwan Science and Technology Innovation Cooperation Project):Mechanism and Key Technologies of CO_(2) Accelerating Mineralization and Storage in Basalt Strata,Project ID:2023YFH0005,2023/01-2025/12Essential Research and Development Plan by Department of Science and Technology in Sichuan Province:Research on Geological Storage and Disaster Prevention of CO_(2)in Deep Saline Water Layer,Project ID:2022YFSY0007,2023/01-2025/12.
文摘It has been found that the rock breaking tools combination of positive displacement motors(PDM)with different output parameters(positive rotational speed and positive torque)and polycrystalline diamond compact(PDC)bits with different design features exhibits significant differences in rock breaking effi-ciency and stability.This indicates that studying the compatibility between PDC bit and PDM before conducting drilling process is necessary.TheΦ215.9 mm wellbore condition in Longmaxi formation was taken as an example,the positive rotational speed and positive torque exerted byΦ197mm PDM with different number of lobes and pitch length were calculated,PDC bit with different cutting strategies were designed.Then finite element method(FEM)models considering PDM output parameters were established to study rock breaking process.Required weight on bit(WOB),required mechanical specific energy(MSE),reaction torque on bit(TOB),and vibration characteristics at near-bit position under the designed rate of penetration(ROP)were obtained.Research results showed that:(1)The energy required for PDC bit with certain design features breaking shale is not a constant value,but a value changes with rotational speed and positive torque exerted by different PDM.(2)The ability controlling vibration of PDM tends to stabilize when the number of lobes N and pitch length h exceeds 5 and 140 mm respectively in general conditions,Thus combination design parameters when N=5,h=140 mm were suggested to balance rock breaking efficiency and service life of drill strings.(3)Compared with other cutting strategies,when rock breaking pattern consist of“face to face”interaction and“point to point”interaction,both rock breaking efficiency and stability were higher.While when matched with this cutting strategy,N=8 and h=140/200 mm were recommended for PDM design instead of N=5 and h=140 mm obtained in most cases,which cloud minimize the loss of rock breaking efficiency and improve the axial/circumferential stability by 14.24%–17.23%and 24.93%–35.73%respectively.An integrated selection and design method of PDC bit and PDM was established and implemented,which revealed the rock breaking efficiency and stability patterns of different rock breaking tools combinations,providing theoretical support and suggestions for the integrated selection and design of PDC bits and PDM in Longmaxi formation.
文摘Spray drying is an important continuous industrial process for drying pumpable liquid formulations irrespective of their heat sensitivity, rheology, solids content and processing rate. Furthermore spray drying has the capability through drying chamber design, plant layout and mode of operation to produce dried products of specific particulate size and morphology. These are important aspects when spray drying technology is applied to the needs of customized powder manufacture. There are many examples in industry where spray dried powders have to meet stringent specifications set by such factors as end-product powder quality standards dictated by global competition,dry raw material characteristics required for optimum downstream processing, and dry materials handling to comply with environmental, health and safety issues. Spray drying is no longer regarded just as a convective industrial drying concept, but also as an integral part of modern manufacturing practices applying powder technology. This paper reviews the aspects of spray dryer design and operation for consideration when customized powder manufacture is involved.
文摘Selection of air conditioning（AC） cold/heat sources generally concerns about certain aspects and cannot reveal the whole profile of the problems. Grey relation analysis （GRA） is a data processing method to categorize the correlation extent of compared sequences and a certain reference sequence in a system with uncertain information. It is applied to evaluating and selecting AC cold/heat sources from four main aspects, which are technology, economy, reliability, and operation and management. Case study shows that the result for selecting AC cold/heat sources with the GRA method can be more reasonable and convincible. Thus it offers a new approach for designers in heating, ventilating and air conditioning field to compare and evaluate different AC cold/heat sou rces.
文摘China's road network consists of numerous older expressways experiencing high traffic volumes and severe congestion,necessitating urgent reconstruction and expansion efforts.This study discusses the reconstruction and expansion project of the Yinkun Expressway's Chongqing High-tech Zone to Rongchang District section,with a detailed exploration of the entire design process.Through a comprehensive analysis,the strengths and weaknesses of different plans are examined,so as to determine the optimal plan.The design chosen saves costs while effectively addressing traffic demands.Additionally,the study summarizes the valuable design insights gained from this interchange transformation,aiming to provide valuable reference for similar interchange projects in the future.
